The mass spectra of large biomolecules (2000 - 10,000 Daltons) will be obtained by Fourier transform mass spectrometry (FTMS). Recent advances in matrix-assisted laser desorption will be used to desorb and ionize large biomolecules for analysis by FTMS. The most recent developments in trapped-ion cell design will be used to construct a cell with high electric-field homogeneity, thus improving the trapping efficiency, mass range and mass resolution of laser-desorbed ions in FTMS. A simple external laser desorption (LD) ion source will be developed to optimally transfer laser-desorbed ions into the trapped-ion cell to further improve the resolution obtained from laser desorption FTMS. Improvements in trapped-ion cell design, laser optics, and external generation of ions will be incorporated into the design of a compact, more economical high-performance LD/FTMS instrument that uses a compact and less expensive laser and superconducting magnet. The FTMS technique has the advantage of very high mass resolution and mass accuracy when compared to dispersive mass spectrometry techniques. The development of techniques for routine analysis of large biomolecules with FTMS will allow sequence and structural information to be obtained by collisionally-activated and photoinduced MS/MS.